/*************************************************************************
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 * 
 * Copyright 2008,2009,2010 by ODENDAHL SEPT-Solutions
 *
 * Office Reader - a OpenDocument viewer for Symbian OS
 *
 * $Id:$
 *
 * This file is part of Office Reader
 *
 * Office Reader is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 or GNU 
 * General Lesser Public License version 3 , as published by the Free Software 
 * Foundation.
 *
 * Office Reader is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General (Lesser) Public License version 3 for more details
 * (a copy is included in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU (Lesser) General Public License
 * version 3 along with Office Reader.  If not, 
 * see <http://www.gnu.org/licenses/>.
 *
 ************************************************************************/

/*
 * Table-driven implementation of the checksum
 * algorithm CRC-32 for Symbian OS.
 *
 * Version: 1.0
 *
 * bit-side GmbH 2005
 * www.bit-side.com
 *
 * Author: Philipp Henkel <p.henkel@bit-side.com>
 * Based on Ross Williams' "Painless Guide to CRC Error
 *                          Detection Algorithms".
 *
 * This code is placed in the public domain.
 *
 *
 * The code is distributed on an 'AS IS' basis, WITHOUT
 * WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 *
 */

#include "crc32.h"


#define POLYNOMIAL 0x04C11DB7



_LIT(KCrc32, "Crc32");

const TUint32 CCrc32::iCrcTable[256] =
{
  0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
  0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
  0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
  0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
  0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
  0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
  0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
  0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
  0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
  0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
  0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
  0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
  0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
  0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
  0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
  0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
  0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
  0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
  0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
  0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
  0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
  0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
  0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
  0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
  0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
  0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
  0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
  0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
  0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
  0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
  0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
  0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
  0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
  0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
  0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
  0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
  0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
  0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
  0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
  0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
  0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
  0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
  0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
  0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
  0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
  0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
  0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
  0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
  0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
  0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
  0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
  0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
  0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
  0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
  0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
  0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
  0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
  0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
  0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
  0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
  0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
  0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
  0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
  0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};




CCrc32::CCrc32()
{
  iCrc = 0xFFFFFFFF;
}


CCrc32::~CCrc32()
{
  // no implementation required
}


CCrc32* CCrc32::NewL()
{
  CCrc32* self = CCrc32::NewLC();
  CleanupStack::Pop(self);
  return self;
}


CCrc32* CCrc32::NewLC()
{
  CCrc32* self = new (ELeave) CCrc32();
  CleanupStack::PushL(self);
  self->ConstructL();
  return self;
}


void CCrc32::ConstructL()
{
#if defined(_DEBUG)
  TInt res = RunSelfTestL();
  if (!res) User::LeaveIfError(KErrGeneral);
#endif
}


void CCrc32::AppendToHashL(const TDesC8& aData)
{
  TInt len =  aData.Size();

  for (TInt idx = 0; idx < len; ++idx)
  {
    iCrc = iCrcTable[(iCrc ^ aData[idx]) & 0xFF] ^ (iCrc >> 8);
  }
}



void CCrc32::HexBytesToHexAscii(const TDesC8& aText, TDes8& aHexCode)
{
  TText8* table = (TText8*)"0123456789ABCDEF";

  __ASSERT_ALWAYS(2*aText.Size() <= aHexCode.MaxSize(), User::Panic(_L("HexBytesToHexAscii"),KErrArgument));
  TInt len = aText.Size();
  TInt c;
  aHexCode.FillZ(2*len);
  for (TInt i = 0; i < len; i++)
  {
    c = aText[i] & 0xFF;
    aHexCode[2*i]   = table[(c >> 4) & 0xF];
    aHexCode[2*i+1] = table[ c       & 0xF];
  }
}



HBufC8* CCrc32::GetHashAndResetL()
{
  // apply final XOR value
  iCrc = iCrc ^ 0xFFFFFFFF;

  HBufC8* buf = HBufC8::NewL(4);
  CleanupStack::PushL(buf);
  TPtr8 pbuf = buf->Des();
  pbuf.FillZ(4);

  pbuf[0] = (TText8)((iCrc >>  24) & 0xFF);
  pbuf[1] = (TText8)((iCrc >>  16) & 0xFF);
  pbuf[2] = (TText8)((iCrc >>   8) & 0xFF);
  pbuf[3] = (TText8)( iCrc         & 0xFF);

  CleanupStack::Pop(buf);

  ResetHash();

  return buf;
}


void CCrc32::ResetHash()
{
  // set intial remainder
  iCrc = 0xFFFFFFFF;
}


#if defined(_DEBUG)
TBool CCrc32::RunSelfTestL()
{
  // check BytesToHex()
  TBuf8<24> aHex;
  HexBytesToHexAscii(_L8("MyTestString"), aHex);
  if(0 != aHex.Compare(_L8("4D7954657374537472696E67")))
  {
    return EFalse;
  }

  // check CRC
  ResetHash();
  AppendToHashL(_L8("123456789"));
  HBufC8* hash = GetHashAndResetL();
  TBuf8<8> asciihash;
  HexBytesToHexAscii(*hash, asciihash);
  if(0 != asciihash.Compare(_L8("CBF43926")))
  {
    delete hash;
    hash = NULL;
    return EFalse;
  }
  delete hash;
  hash = NULL;

  return ETrue;
}

#endif








